Probing the neutron star spin evolution in the young SMC Be/X-ray binary SXP 1062

TL;DR

This paper investigates the young neutron star in the SMC Be/X-ray binary SXP 1062, exploring its spin evolution and magnetic field decay to understand its unusual long spin period and recent supernova remnant association.

Contribution

It proposes that SXP 1062's neutron star was born with an extremely strong magnetic field that decayed over time, explaining its current properties.

Findings

SXP 1062 is the youngest known Be/X-ray binary with a supernova remnant.

The neutron star likely had an initial magnetic field > 10^14 G that decayed to ~10^13 G.

Possible evolutionary scenarios include a fossil disc or long initial spin period.

Abstract

The newly discovered Be/X-ray binary in the Small Magellanic Cloud, SXP 1062, provides the first example of a robust association with a supernova remnant (SNR). The short age estimated for the SNR qualifies SXP 1062 as the youngest known source in its class, tau ~ 1e4 yr. As such, it allows to test current models of magneto-rotational evolution of neutron stars ina still unexplored regime. Here we discuss possible evolutionary scenarios for SXP 1062 in the attempt to reconcile its long spin period, P=1062 s, and short age. Although several options can be considered, like an anomalously long initial period or the presence of a fossil disc, our results indicate that SXP 1062 may host a neutron star born with a large initial magnetic field, typically in excess of ~ 1e14 G, which then decayed to ~ 1e13 G.